Treatment with pimitespib has been found to be associated with stable disease in two-thirds of patients with advanced gastrointestinal stromal tumors (GISTs) in an expanded access program.
Findings from the program were published in the International Journal of Clinical Oncology.
Pimitespib was approved for use in Japan as a fourth-line treatment for GIST in June 2022. The approval was based on the results of the CHAPTER-GIST-301 study, where fourth-line treatment with pimitespib was found to extend progression-free survival to a median of 2.8 months versus 1.4 months among patients who received placebo.
The expanded access program documented in the International Journal of Clinical Oncology was undertaken befo
Glossary:
Progression-free survival: the time a patient lives without their disease spreading or worsening.
Complete response: the disappearance of all signs of cancer in response to treatment, according to the National Cancer Institute.
Partial response: a decrease in the size of a tumor, or in the extent of cancer in the body, in response to treatment, according to the National Cancer Institute.
Stable disease: cancer that is neither decreasing nor increasing in extent or severity, according to the National Cancer Institute.
Progressive disease: cancer that is growing, spreading, or getting worse, according to the National Cancer Institute.
re pimitespib was authorized for marketing in Japan in order to offer treatment opportunities to patients with advanced GIST who had already received standard treatment.
“In conclusion, the results of this study show that pimitespib was well tolerated and effective in patients with advanced GIST in Japan,” Dr. Yoichi Naito and co-authors wrote in the study. “These findings support the safety profile demonstrated by pimitespib in the phase 2 and CHAPTER-GIST-301 studies, with no new safety concerns identified.”
Naito is part of the Department of General Internal Medicine, Medical Oncology, Experimental Therapeutics, National Cancer Center Hospital East, in Kashiwa, Japan.
Twenty-three patients were enrolled between February and August 2022, and the disease-control rate was 66.7%. Among the 21 patients in the study’s full analysis set, no patients had a complete response or partial response to treatment, while 14 patients (66.7%) had stable disease, five patients (23.8%) had progressive disease and response could not be evaluated in two patients (9.5%).
Tumor shrinkage of approximately 10% was observed in two patients. Progression-free survival events occurred in 12 patients (57.1%) and the median progression-free survival time was 4.2 months.
Over a median treatment duration of 81 days, side effects occurred in 22 patients (95.7%), with the most common side effects being diarrhea (79.3%), nausea (39.1%) and increased blood creatinine (30.4%). While serious side effects offered in two patients, tumor hemorrhage and tumor pain, neither was found to be related to pimitespib, and one patient’s case of grade 3 (severe) diarrhea was considered treatment-related. Additionally, four patients, or 17.4%, experienced eye disorders, all of which were reported to be grade 1 (mild) and treatment-related.
Pimitespib, according to an article published in Future Oncology, is an oral medication that works by inhibiting a protein called heat shock protein 90, stopping cancer cells from developing and growing.
GISTs are relatively uncommon cancers that start in special cells in the wall of the gastrointestinal tract, also known as the digestive tract, according to the American Cancer Society, which estimates that there are approximately 4,000 to 6,000 cases of GIST diagnosed in the United States each year.
Reference:
“Pimitespib in patients with advanced gastrointestinal stromal tumors in Japan: an expanded access program” by Dr. Yoichi Naito1 et al., International Journal of Clinical Oncology.
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